1. Field of the Invention
The present invention relates to a storage control apparatus, a storage control program, and a storage control method that collect the backup of storage data in units of generation.
2. Description of the Related Art
Generally, a computer system collects the backup of storage data for data restoration from a system failure or operation error. As an enhanced copy function for use in making a backup, OPC (One Point Copy) and EC (Equivalent Copy) are known. A main function of the OPC is to create a snapshot, by which data in a copy destination storage serves as data in a copy source storage in the time point when a copy instruction is issued. A main function of EC is to create a mirror, by which data in a copy destination storage synchronizes with data in a copy source storage during a specified time period.
As a conventional art related to the present invention, there is known a generation management system concerning a snapshot image, which includes a data holding section that stores a snapshot image at a given time point and another data holding section that stores subsequent updated data, updated areas, and generations (refer to Pat. Document 1: Jpn. Pat. Appln. Laid-Open Publication No. 2005-292865).
In view of data restoration from backup data, it is desirable to collect backup over a plurality of generations at fine time intervals. However, in the conventional art, it has been necessary to prepare volumes each having the same capacity as a backup source storage by the number corresponding to backup generations. Further, in a technique like Pat. Document 1, it is necessary to newly add a mirroring function for simultaneously writing data both for current generation and backup and a path configuration for use in the mirroring operation in advance. Further, with a lapse of time from the initial copy processing, the number of updated data is increased to increase a load involved with a data restoration process.